﻿#if NET45
using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.Dynamic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.Serialization.Json;
using System.Text;
using System.Xml;
using System.Xml.Linq;
public class DynamicJson : DynamicObject
{
    private enum JsonType
    {
        @string, number, boolean, @object, array, @null
    }

    // public static methods

    /// <summary>from JsonSring to DynamicJson</summary>
    public static dynamic Parse(string json)
    {
        return Parse(json, Encoding.Unicode);
    }

    /// <summary>from JsonSring to DynamicJson</summary>
    public static dynamic Parse(string json, Encoding encoding)
    {
        using (var reader = JsonReaderWriterFactory.CreateJsonReader(encoding.GetBytes(json), XmlDictionaryReaderQuotas.Max))
        {
            return ToValue(XElement.Load(reader));
        }
    }

    /// <summary>from JsonSringStream to DynamicJson</summary>
    public static dynamic Parse(Stream stream)
    {
        using (var reader = JsonReaderWriterFactory.CreateJsonReader(stream, XmlDictionaryReaderQuotas.Max))
        {
            return ToValue(XElement.Load(reader));
        }
    }

    /// <summary>from JsonSringStream to DynamicJson</summary>
    public static dynamic Parse(Stream stream, Encoding encoding)
    {
        using (var reader = JsonReaderWriterFactory.CreateJsonReader(stream, encoding, XmlDictionaryReaderQuotas.Max, _ => { }))
        {
            return ToValue(XElement.Load(reader));
        }
    }

    /// <summary>create JsonSring from primitive or IEnumerable or Object({public property name:property value})</summary>
    public static string Serialize(object obj)
    {
        return CreateJsonString(new XStreamingElement("root", CreateTypeAttr(GetJsonType(obj)), CreateJsonNode(obj)));
    }

    // private static methods

    private static dynamic ToValue(XElement element)
    {
        var type = (JsonType)Enum.Parse(typeof(JsonType), element.Attribute("type").Value);
        switch (type)
        {
            case JsonType.boolean:
                return (bool)element;
            case JsonType.number:
                return (double)element;
            case JsonType.@string:
                return (string)element;
            case JsonType.@object:
            case JsonType.array:
                return new DynamicJson(element, type);
            case JsonType.@null:
            default:
                return null;
        }
    }

    private static JsonType GetJsonType(object obj)
    {
        if (obj == null) return JsonType.@null;

        switch (Type.GetTypeCode(obj.GetType()))
        {
            case TypeCode.Boolean:
                return JsonType.boolean;
            case TypeCode.String:
            case TypeCode.Char:
            case TypeCode.DateTime:
                return JsonType.@string;
            case TypeCode.Int16:
            case TypeCode.Int32:
            case TypeCode.Int64:
            case TypeCode.UInt16:
            case TypeCode.UInt32:
            case TypeCode.UInt64:
            case TypeCode.Single:
            case TypeCode.Double:
            case TypeCode.Decimal:
            case TypeCode.SByte:
            case TypeCode.Byte:
                return JsonType.number;
            case TypeCode.Object:
                return (obj is IEnumerable) ? JsonType.array : JsonType.@object;
            case TypeCode.DBNull:
            case TypeCode.Empty:
            default:
                return JsonType.@null;
        }
    }

    private static XAttribute CreateTypeAttr(JsonType type)
    {
        return new XAttribute("type", type.ToString());
    }

    private static object CreateJsonNode(object obj)
    {
        var type = GetJsonType(obj);
        switch (type)
        {
            case JsonType.@string:
            case JsonType.number:
                return obj;
            case JsonType.boolean:
                return obj.ToString().ToLower();
            case JsonType.@object:
                return CreateXObject(obj);
            case JsonType.array:
                return CreateXArray(obj as IEnumerable);
            case JsonType.@null:
            default:
                return null;
        }
    }

    private static IEnumerable<XStreamingElement> CreateXArray<T>(T obj) where T : IEnumerable
    {
        return obj.Cast<object>()
            .Select(o => new XStreamingElement("item", CreateTypeAttr(GetJsonType(o)), CreateJsonNode(o)));
    }

    private static IEnumerable<XStreamingElement> CreateXObject(object obj)
    {
        return obj.GetType()
            .GetProperties(BindingFlags.Public | BindingFlags.Instance)
            .Select(pi => new { Name = pi.Name, Value = pi.GetValue(obj, null) })
            .Select(a => new XStreamingElement(a.Name, CreateTypeAttr(GetJsonType(a.Value)), CreateJsonNode(a.Value)));
    }

    private static string CreateJsonString(XStreamingElement element)
    {
        using (var ms = new MemoryStream())
        using (var writer = JsonReaderWriterFactory.CreateJsonWriter(ms, Encoding.Unicode))
        {
            element.WriteTo(writer);
            writer.Flush();
            return Encoding.Unicode.GetString(ms.ToArray());
        }
    }

    // dynamic structure represents JavaScript Object/Array

    readonly XElement xml;
    readonly JsonType jsonType;

    /// <summary>create blank JSObject</summary>
    public DynamicJson()
    {
        xml = new XElement("root", CreateTypeAttr(JsonType.@object));
        jsonType = JsonType.@object;
    }

    private DynamicJson(XElement element, JsonType type)
    {
        Debug.Assert(type == JsonType.array || type == JsonType.@object);

        xml = element;
        jsonType = type;
    }

    public bool IsObject { get { return jsonType == JsonType.@object; } }

    public bool IsArray { get { return jsonType == JsonType.array; } }

    /// <summary>has property or not</summary>
    public bool IsDefined(string name)
    {
        return IsObject && (xml.Element(name) != null);
    }

    /// <summary>has property or not</summary>
    public bool IsDefined(int index)
    {
        return IsArray && (xml.Elements().ElementAtOrDefault(index) != null);
    }

    /// <summary>delete property</summary>
    public bool Delete(string name)
    {
        var elem = xml.Element(name);
        if (elem != null)
        {
            elem.Remove();
            return true;
        }
        else return false;
    }

    /// <summary>delete property</summary>
    public bool Delete(int index)
    {
        var elem = xml.Elements().ElementAtOrDefault(index);
        if (elem != null)
        {
            elem.Remove();
            return true;
        }
        else return false;
    }

    /// <summary>mapping to Array or Class by Public PropertyName</summary>
    public T Deserialize<T>()
    {
        return (T)Deserialize(typeof(T));
    }

    private object Deserialize(Type type)
    {
        return (IsArray) ? DeserializeArray(type) : DeserializeObject(type);
    }

    private dynamic DeserializeValue(XElement element, Type elementType)
    {
        var value = ToValue(element);
        if (value is DynamicJson)
        {
            value = ((DynamicJson)value).Deserialize(elementType);
        }
        return Convert.ChangeType(value, elementType);
    }

    private object DeserializeObject(Type targetType)
    {
        var result = Activator.CreateInstance(targetType);
        var dict = targetType.GetProperties(BindingFlags.Public | BindingFlags.Instance)
            .Where(p => p.CanWrite)
            .ToDictionary(pi => pi.Name, pi => pi);
        foreach (var item in xml.Elements())
        {
            PropertyInfo propertyInfo;
            if (!dict.TryGetValue(item.Name.LocalName, out propertyInfo)) continue;
            var value = DeserializeValue(item, propertyInfo.PropertyType);
            propertyInfo.SetValue(result, value, null);
        }
        return result;
    }

    private object DeserializeArray(Type targetType)
    {
        if (targetType.IsArray) // Foo[]
        {
            var elemType = targetType.GetElementType();
            dynamic array = Array.CreateInstance(elemType, xml.Elements().Count());
            var index = 0;
            foreach (var item in xml.Elements())
            {
                array[index++] = DeserializeValue(item, elemType);
            }
            return array;
        }
        else // List<Foo>
        {
            var elemType = targetType.GetGenericArguments()[0];
            dynamic list = Activator.CreateInstance(targetType);
            foreach (var item in xml.Elements())
            {
                list.Add(DeserializeValue(item, elemType));
            }
            return list;
        }
    }

    // Delete
    public override bool TryInvoke(InvokeBinder binder, object[] args, out object result)
    {
        result = (IsArray)
            ? Delete((int)args[0])
            : Delete((string)args[0]);
        return true;
    }

    // IsDefined, if has args then TryGetMember
    public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result)
    {
        if (args.Length > 0)
        {
            result = null;
            return false;
        }

        result = IsDefined(binder.Name);
        return true;
    }

    // Deserialize or foreach(IEnumerable)
    public override bool TryConvert(ConvertBinder binder, out object result)
    {
        if (binder.Type == typeof(IEnumerable) || binder.Type == typeof(object[]))
        {
            var ie = (IsArray)
                ? xml.Elements().Select(x => ToValue(x))
                : xml.Elements().Select(x => (dynamic)new KeyValuePair<string, object>(x.Name.LocalName, ToValue(x)));
            result = (binder.Type == typeof(object[])) ? ie.ToArray() : ie;
        }
        else
        {
            result = Deserialize(binder.Type);
        }
        return true;
    }

    private bool TryGet(XElement element, out object result)
    {
        if (element == null)
        {
            result = null;
            return false;
        }

        result = ToValue(element);
        return true;
    }

    public override bool TryGetIndex(GetIndexBinder binder, object[] indexes, out object result)
    {
        return (IsArray)
            ? TryGet(xml.Elements().ElementAtOrDefault((int)indexes[0]), out result)
            : TryGet(xml.Element((string)indexes[0]), out result);
    }

    public override bool TryGetMember(GetMemberBinder binder, out object result)
    {
        return (IsArray)
            ? TryGet(xml.Elements().ElementAtOrDefault(int.Parse(binder.Name)), out result)
            : TryGet(xml.Element(binder.Name), out result);
    }

    private bool TrySet(string name, object value)
    {
        var type = GetJsonType(value);
        var element = xml.Element(name);
        if (element == null)
        {
            xml.Add(new XElement(name, CreateTypeAttr(type), CreateJsonNode(value)));
        }
        else
        {
            element.Attribute("type").Value = type.ToString();
            element.ReplaceNodes(CreateJsonNode(value));
        }

        return true;
    }

    private bool TrySet(int index, object value)
    {
        var type = GetJsonType(value);
        var e = xml.Elements().ElementAtOrDefault(index);
        if (e == null)
        {
            xml.Add(new XElement("item", CreateTypeAttr(type), CreateJsonNode(value)));
        }
        else
        {
            e.Attribute("type").Value = type.ToString();
            e.ReplaceNodes(CreateJsonNode(value));
        }

        return true;
    }

    public override bool TrySetIndex(SetIndexBinder binder, object[] indexes, object value)
    {
        return (IsArray)
            ? TrySet((int)indexes[0], value)
            : TrySet((string)indexes[0], value);
    }

    public override bool TrySetMember(SetMemberBinder binder, object value)
    {
        return (IsArray)
            ? TrySet(int.Parse(binder.Name), value)
            : TrySet(binder.Name, value);
    }

    public override IEnumerable<string> GetDynamicMemberNames()
    {
        return (IsArray)
            ? xml.Elements().Select((x, i) => i.ToString())
            : xml.Elements().Select(x => x.Name.LocalName);
    }

    /// <summary>Serialize to JsonString</summary>
    public override string ToString()
    {
        // <foo type="null"></foo> is can't serialize. replace to <foo type="null" />
        foreach (var elem in xml.Descendants().Where(x => x.Attribute("type").Value == "null"))
        {
            elem.RemoveNodes();
        }
        return CreateJsonString(new XStreamingElement("root", CreateTypeAttr(jsonType), xml.Elements()));
    }
}
#endif
